649009 has 4 divisors (see below), whose sum is σ = 687204. Its totient is φ = 610816.

The previous prime is 649007. The next prime is 649039. The reversal of 649009 is 900946.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 900946 = 2 ⋅450473.

It can be written as a sum of positive squares in 2 ways, for example, as 230400 + 418609 = 480^2 + 647^2 .

It is a cyclic number.

It is not a de Polignac number, because 649009 - 2¹ = 649007 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (649001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19072 + ... + 19105.

It is an arithmetic number, because the mean of its divisors is an integer number (171801).

2⁶⁴⁹⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

649009 is a deficient number, since it is larger than the sum of its proper divisors (38195).

649009 is a wasteful number, since it uses less digits than its factorization.

649009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38194.

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 649009 is about 805.6109482871. The cubic root of 649009 is about 86.5798654270.

The spelling of 649009 in words is "six hundred forty-nine thousand, nine".